全文获取类型
收费全文 | 1345855篇 |
免费 | 92410篇 |
国内免费 | 4242篇 |
专业分类
耳鼻咽喉 | 16899篇 |
儿科学 | 43604篇 |
妇产科学 | 36356篇 |
基础医学 | 198094篇 |
口腔科学 | 35948篇 |
临床医学 | 129811篇 |
内科学 | 258768篇 |
皮肤病学 | 26389篇 |
神经病学 | 112229篇 |
特种医学 | 48204篇 |
外国民族医学 | 366篇 |
外科学 | 184209篇 |
综合类 | 28883篇 |
现状与发展 | 1篇 |
一般理论 | 460篇 |
预防医学 | 114496篇 |
眼科学 | 29067篇 |
药学 | 99049篇 |
35篇 | |
中国医学 | 3202篇 |
肿瘤学 | 76437篇 |
出版年
2021年 | 11162篇 |
2019年 | 12142篇 |
2018年 | 16370篇 |
2017年 | 12383篇 |
2016年 | 13279篇 |
2015年 | 15221篇 |
2014年 | 20830篇 |
2013年 | 32056篇 |
2012年 | 44234篇 |
2011年 | 46883篇 |
2010年 | 27072篇 |
2009年 | 24919篇 |
2008年 | 42711篇 |
2007年 | 45056篇 |
2006年 | 45163篇 |
2005年 | 43583篇 |
2004年 | 41560篇 |
2003年 | 39491篇 |
2002年 | 38306篇 |
2001年 | 60843篇 |
2000年 | 62513篇 |
1999年 | 52277篇 |
1998年 | 14579篇 |
1997年 | 13274篇 |
1996年 | 13117篇 |
1995年 | 12458篇 |
1994年 | 11628篇 |
1993年 | 10922篇 |
1992年 | 41569篇 |
1991年 | 40760篇 |
1990年 | 39445篇 |
1989年 | 37340篇 |
1988年 | 34581篇 |
1987年 | 33695篇 |
1986年 | 32152篇 |
1985年 | 30639篇 |
1984年 | 23034篇 |
1983年 | 19589篇 |
1982年 | 11754篇 |
1979年 | 20804篇 |
1978年 | 14814篇 |
1977年 | 12064篇 |
1976年 | 11876篇 |
1975年 | 12110篇 |
1974年 | 14800篇 |
1973年 | 14472篇 |
1972年 | 13356篇 |
1971年 | 12418篇 |
1970年 | 11485篇 |
1969年 | 10410篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
Relaxing retinotomies. Analysis of anatomic and visual results 总被引:6,自引:0,他引:6
The authors analyzed 100 consecutive eyes undergoing relaxing retinotomies to determine the anatomic and visual results associated with the use of this procedure. With a minimum follow-up of 6 months, 58 eyes were completely attached, 8 were partially attached (macula on), and 34 were detached. Thirty-four percent of all eyes and 50% of attached eyes obtained a visual acuity of 5/200 or greater at 6 months. At last examination, 29% of all eyes and 43% of attached eyes had a visual acuity of at least 5/200. Eyes that had circumferential relaxing retinotomies involving the entire temporal quadrant generally had lower visual acuities when compared with eyes that had relaxing retinotomies sparing the entire temporal quadrant. The use of a radial relaxing retinotomy also was associated with lower final visual acuity. The length of the relaxing retinotomy or the placement of the relaxing retinotomy either anterior or posterior to the encircling scleral buckle did not appear to influence the anatomic or visual results. Hypotony (intraocular pressure less than 5 mmHg) was seen in 43% of reattached eyes. 相似文献
992.
993.
Auxiliary production of antibodies to ocular antigens in experimental autoimmune uveoretinitis 总被引:1,自引:0,他引:1
In experimental autoimmune uveoretinitis (EAU), there are concurrent autoreactive humoral and cellular immune responses. Many studies have recently focused on T-cell reactivities in EAU, while analysis of autoantibody responses to uveitogenic epitopes has been less well characterized. In this study, a defined 16-mer uveitogenic interphotoreceptor retinoid binding protein (IRBP) peptide, designated #896, was used to induce EAU. Histological analysis of eyes at day 10 demonstrated extensive leukocyte infiltration of the anterior segment, with mononuclear and plasma cells in the posterior segment. The presence of plasma cells suggests local production of antibodies within the eye. ELISA analyses of serum, aqueous, and vitreous from rats with IRBP-induced, severe EAU revealed the presence of antibodies against peptide #896. There was little difference between the serum and intraocular antibody titers, presumably due to breakdown of the blood-ocular barriers. In addition to the anti-#896-IRBP antibodies, there were detectable antibodies reactive against separate and distinct IRBP epitopes, as well as, against epitopes on retinal-S antigen. These results indicate that in #896-peptide-induced severe EAU, humoral immune responses are induced to the primary immunogen and that there is also auxiliary production of autoreactive antibodies against other epitopes present on intraocular antigens. These auxiliary responses may contribute to the immunopathogenesis of severe EAU. 相似文献
994.
The condition of newborn infants with anencephaly, a neural tube defect, is incurable and uniformly fatal. Although physicians reached a consensus two decades ago on the appropriateness of using these infants' organs, ethical and legal questioning has since challenged the grounds on which medical authorities justified transplantation. Advocates have proposed three conceptual strategies to warrant procuring anencephalics' organs: redefining death, excluding the infants from possessing personhood, and intubating and ventilating them while keeping a vigil for brain death. Each of these conceptual schemes has arguable shortcomings in its construction, however; as such, the case for using anencephalic infants as sources of organs has yet to be conclusively demonstrated. 相似文献
995.
S L Lehmann K M Teasley N N Konstantinides F Konstantinides F B Cerra 《Journal of the American College of Nutrition》1990,9(6):610-615
The purpose of this pilot study was to investigate the metabolic effects of growth hormone (GH) (Humatrope, Eli Lilly & Co., Indianapolis, IN) administration in postoperative (PO) patients receiving peripheral vein nutrition. Seven, well-nourished, nondiabetic patients undergoing elective surgical procedures were given either no drug (n = 3), GH 30 micrograms/kg/day (n = 2), or GH 60 micrograms/kg/day (n = 2) sub-Q daily until eating, up to 7 days PO. All the patients received 5% dextrose with electrolytes in the first 24 hours PO and then received calories at 80 +/- 5% of the measured resting energy expenditure (REE) and amino acid at 1 g/kg/day with electrolytes, vitamins, and minerals. There were no significant outcome differences between the 30 and 60 micrograms/kg/day groups and, therefore, these groups were analyzed together (n = 4). By day 6 of the study, the GH group had a significant reduction in the respiratory quotient (RQ) measured by indirect calorimetry; an increase in nitrogen retention; an increase in plasma transferrin concentrations; and an increase in plasma insulinlike growth factor (IGF1) concentration. There was no increase in blood glucose concentrations, or decrease in urinary 3-methylhistidine excretion; and no adverse effects occurred. We concluded that GH in PO patients on hypocaloric nutrition promoted protein synthesis, fat oxidation, and nitrogen retention. Effective parenteral nutritional support in postoperative adult patients can be achieved without the use of central vein access. 相似文献
996.
J Amaro Labrador I Gato Chamizo M L Venero Hernández 《Revista cubana de enfermería》1990,6(1):118-127
This paper studies all cases affected by 5 parotiditis from January to September 1986 (1767 cases) and 1987 (124 cases), as well as all patients with rubella reported in the same period in 1986 (584 cases) and 1987 (5 cases) in the province of Pinar del Río. The rise in the incidence of the two diseases with an annual basis per 100,000 population during 1986 in the different municipalities is emphasized. The overtly downward trend of these two diseases in 1987 after the administration of the triple viral vaccine--93% for mumps and 99.15% for rubella--is discussed. It was found that these two diseases affected more often school children (5-14 years). It was found that these two diseases are not frequent under the first year of life (76.4 and 120.1 cases per 100,000 population respectively). The percentage of vaccine effectiveness was documented--97.4% for parotiditis and 100% for rubella. 相似文献
997.
An 80-year-old man was evaluated for an epibulbar tumor on a phthisical eye. The initial biopsy diagnosis of the epibulbar tumor was poorly differentiated neoplasm. Exenteration of the phthisical eye and orbital contents showed an extensive pleomorphic adenocarcinoma of the nonpigmented epithelium of the ciliary body with extraocular extension. There was evidence of hyaluronic acid secretion and immunohistochemical staining was strong for vimentin, focal for epithelial membrane antigen and S-100 protein, and weak for neuron-specific-enolase. Electron microscopy demonstrated desmosomes between tumor cells, areas of thick, multilaminar basement membrane production surrounding individual tumor cells, and occasional intracytoplasmic intermediate filaments. 相似文献
998.
Brightness discrimination and contrast sensitivity in chronic glaucoma--a clinical study. 总被引:1,自引:0,他引:1
The visual acuity, the difference in sensitivity of the two eyes to light (brightness ratio), and contrast sensitivity were assessed in 28 patients with chronic open angle glaucoma and compared with those of 41 normal controls of similar ages and visual acuity. The results obtained were related to the results of Tübingen visual field analysis in patients with glaucoma. Twenty-four of the 28 glaucoma patients (86%) had a significant disparity in brightness ratio between the two eyes. This was found to match the frequency of visual field loss. Moreover, there was a significant relationship between the interocular differences in brightness sense and the difference in the degree of visual field loss between the two eyes. Of the glaucoma patients 39% had sum contrast sensitivities outside the normal range for age-matched normal controls. No significant correlation was found between the interocular difference in brightness sense and the visual acuity or the interocular difference in sum contrast sensitivity. It is concluded that, in the presence of a normal visual acuity, the brightness ratio test warrants evaluation as a potential screening test for chronic open angle glaucoma. 相似文献
999.
We treated 40 eyes of 40 patients by using noncontact transscleral Nd:YAG cyclophotocoagulation to determine whether treatment 1.5 or 3.0 mm posterior to the corneoscleral lumbus was preferable. Patients were randomly assigned to one of the treatment groups, and all other variables, including power, number, and distribution of laser applications, were kept constant. Six months postoperatively, those treated 1.5 mm posterior to the corneoscleral limbus had a lower intraocular pressure (P = .0047) than those treated 3.0 mm from the corneoscleral limbus. The 1.5-mm group also required fewer retreatment (P = .017) and had a slightly lower occurrence of visual acuity loss after this procedure. We believe it may be advantageous to locate the laser application approximately 1.5 mm posterior to the corneoscleral limbus, rather than further posteriorly, when performing noncontact transscleral Nd:YAG cyclophotocoagulation. 相似文献
1000.
J. P. H. DRENTH L. P. BOS L. G. J. B. ENGELS 《Alimentary pharmacology & therapeutics》1990,4(4):411-416
Calcium antagonist relax smooth muscle, a possible useful concept in treatment of diffuse oesophageal spasm. Therefore the effects of oral diltiazem (60 mg t.d.s.) and placebo were compared in eight patients with diffuse oesophageal spasm in a 10-week double-blind crossover study. The patients recorded the severity of chest pain and/or dysphagia in daily pain diaries using visual analogue scales. Chest pain index and dysphagia index were calculated by multiplying frequency with daily intensity of each individual symptom. When compared to placebo, diltiazem did not significantly change the overall dysphagia index and chest pain index. An individual sizeable reduction of dysphagia was attained on diltiazem in four out of six patients and in six out of eight patients suffering from chestpain. Side effects were not seen during diltiazem therapy. Diltiazem, in our study, did not yield in a significant improvement of symptoms in diffuse oesophageal spasm. Diltiazem, however, can offer relief in selected individual patients suffering from diffuse oesophageal spasm. 相似文献